Thermal design of BESⅢ magnet

摘要

This paper presents the thermal analysis of Beijing Spectrometer Magnet (BESⅢ magnet) which will be used as a superconducting detector magnet in BEPC-Ⅱ. BEPC-Ⅱ is an upgrade project to the Beijing Electron Positron Collider (BEPC). BESⅢ Magnet is cooled by forced flow of two phase helium and the inner winding technique is adopted in the coil winding process. A 3D model of calculation for the magnet was built. The heat load and the temperature distribution of the magnet were analyzed by a finite element method, and the upper limits of several heat leak sources were calculated.